Process for treating infertility

ABSTRACT

A combination of gonadotrophins and growth hormone is useful for treating infertility in higher mammals and humans since the probability of pregnancy is enhanced. In the treatment, gonadotrophins and growth hormone are injected separately, or a combined preparation containing both of these active substances may be used.

This is a continuation of co-pending application Ser. No. 07/064,846 filed on June 19, 1987, now abandoned.

The present invention concerns a process for treating infertility in higher mammals or humans. The invention also concerns an agent for use in the process.

Higher mammals and humans of the female sex are born with a large number of oocytes. For women, the number of egg cells is about 200,000 in each ovary. After birth, many egg cells are lost before pubescence, and no new ones are formed.

The oocytes are surrounded by a ring of epithelial cells, so-called granulose cells. The egg cell with the surrounding granulosa cells is called the follicle.

The ovarian function of higher mammals and humans is regulated by pituitary sex hormones, called gonadotrophins. These include the follicle stimulating hormone (FSH) which causes follicle maturation, and the luteinizing hormone (LH) which causes ovulation.

At the beginning of each menstruation the ovaries are affected by the FSH hormone, so that a plurality of follicles grows, several layers of granulosa cells are being formed, and the follicle is also surrounded by cells formed from the surrounding tissue, the theca cells.

Gradually, one follicle takes the lead, and the others degenerate. Normally, maturation of this one follicle takes 10 to 12 days. Also the amount of theca cells increases during the follicle maturation. Oestrogens are formed from these cells, and therefore increasing secretion of oestrogens will be a result of and thus a measure of the follicle maturation.

Halfway in the menstrual cycle the mature follicle bursts under the action of the LH released from the hypophysis, and the egg is discharged, ovulation. The egg passes out to the abdominal cavity and is caught by one Fallopian tube, through which it is conveyed to the uterus.

The follicle which has discharged the egg is transformed to a new hormone producing organ, the corpus luteum. Corpus luteum develops fully during the following days and produces progesterone together with oestrogens. Since progesterone is produced only in the corpus luteum, detection of progesterone implies ovulation with formation of a corpus luteum.

Corups luteum has a limited life of about 12-14 days. Then, it very quickly ceases functioning, and the blood content of oestrogens and progesterone drops abruptly. This decline causes necrosis of the lining of the uterus, and menstruation usually occurs 13 or 14 days after the ovulation.

The production and release of FSH and LH by the hypophysis is controlled partly from hypothalamus (a part of the brain positioned just above the hypophysis) by release of gonadotrophin releasing hormone (GnRH) and partly via a feed-back mechanism conditional upon the oestrogen production in the ovaries.

Release and activity of GnRH is modified by a so-called negative feed-back mechanism, since increased oestrogen production and thus increased oestrogen concentration in the blood take place in step with the follicle maturation. The increased oestrogen concentration impairs (i.e. has a negative effect on) secretion of FSH and LH from the hypophysis. Correspondingly, low oestrogen concentrations do not impair the GnRH secretion, and the release of GnRH from hypothalamus stimulates the release of FSH and LH from the hypophysis. The causes of infertility in women include:

1) Abnormal ovarian function (primary ovarian failure)

2) Reduced hypothalamus-hypophysis function, i.e. hypophysis insufficiency, causing ovulatory failure (secondary ovarian failure)

3) Tubal damage (adhesions, obstruction, etc.)

4) Endometriosis (the presence of membranous material of the kind lining the uterus at other sites within the cavity of the pelvis).

Injections of gonadotrophins are used to treat infertility caused by hypophysis insufficiency. Usually, in the case of absent ovulation, first, daily injections are administered with preparations having FSH activity, such as menotrophin, until a pre-ovulation oestrogen content in urine or plasma can be detected. Then, one or two injections of chorionic gonadotrophin are administered, which cause ovulation and the formation and function of a corpus luteum.

The use of gonadotrophin preparations is not a certain method of treating infertility because a percentage of the treated women does not become pregnant. Further, the treatments involve a considerable risk, because overstimulation easily occurs, which may cause big ovarian cysts, liquid or blood accumulations in the abdominal cavity and liquid accumulation in the thoracic cavity. Further, there is a risk of multiple pregnancy (twins, triplets, quadruplets, etc.).

It is known that insulin and several of the growth factors can modify some of the actions of gonadotrophins and granulosa cells (1). In these studies, granulosa cells from rats and pigs were cultured with FSH in serum free media in the presence of insulin, insulin-like growth factor 1 (IGF-1), transforming growth factor-beta (TGF-beta) and epidermal growth factor (EGF). These experiments showed that insulin and IGF-1 enhanced and EGF inhibited these actions of FSH. TGF-beta has been found to increase granulose cell aromatase activity (2).

In another series of experiments (3) it was shown that treatment of rats with growth hormone enhanced ovarian production of IGF-1.

The present invention is based on the surprising finding that growth hormones have a synergistic effect on gonadotrophins to stimulate ovarian function.

The process of the invention is thus characterized by treating the infertile individual with injections of a combination of gonadotrophins and growth hormone.

Owing to the synergistic effect it is possible to obtain a more certain result, i.e. the number of infertile women who become pregnant after a treatment is increased in percent. Further, the necessary dose of gonadotrophins is reduced considerably, so that the danger of overdose is highly reduced.

The treatment may be performed on infertile farm animals, such as cows, pigs, sheep and minks. Further, infertile women can be treated with the present process so that ovarian function is normalized, and the chance of pregnancy is improved considerably.

According to the invention, the treatment may be performed with separate injections of gonadotrophins and growth hormone, respectively, over certain intervals of time. The normal treatment with gonadotrophins consists in daily injections with a gonadotrophin preparation. When this injection is supplemented every other day with growth hormone, ovarian response is improved considerably. Instead, in a preferred embodiment of the process of the invention, a mixed preparation of gonadotrophins and growth hormone may be used, the dose size of the single components being adjusted individually. The amount of gonadotrophins is kept at a lower level so that overdosing is avoided, while providing an optimum effect.

To carry out the invention, use is made of an agent or an injection preparation which may expediently contain gonadetrophins and growth hormone in optimum or individually adapted amounts, distributed in a physiologically acceptable carrier of a type known per se in connection with injection preparations.

The growth hormone used should be the growth hormone specific to the species in question. Accordingly, human growth hormone, hGH, which may be biosynthetically produced, is used for women, and bovine GH for cattle, etc.

Infertility among couples is estimated to have an annual incidence of 1.2 couples for every 1,000 of the population (ref. 4). Of these couples around 20% have infertility problems due to abnormal gonadotrophin secretion causing avulatory failure (hypogonadotrophic hypogonadism, secondary ovarian failure).

"The indication for the combined treatment with gonadotrophin and hGH is hypogonadotrophic hypogonadism resistant to treatment with synthetic drugs stimulating ovulation (such as `clomiphene`) and where high doses of gonadogrophins are needed to develop mature follicles and eggs"

In patients with normal gonadotrophin secretion but abnormal ovaries (primary ovarian failure) the combined treatment with gonadotrophin and hGH is not expected to induce ovulation. Therefore, primary ovarian failure is not an indication for this kind of treatment.

Treatment with gonadotrophin and hGH can be used for "in vivo fertilization" where the objective is to obtain maturation of a single follicle and egg (oocyte) with the subsequent fertilization of this egg typically taking place the natural way, i.e. in the Fallopian tube. The above treatment can also be used for "in vitro fertilization", where the objective is to obtain as many mature follicles and eggs as possible. Next, the best looking eggs are removed (aspirated) from the patient's ovaries, and the subsequent fertilization of the eggs takes place in the laboratory. Hereafter a fertilized egg is placed in the uterine mucose of the patient, where the development of the egg continues.

The effect of treatment with gonadotrophin and hGH is hypogonadotrophic hypogonadism is illustrated below by means of 4 examples. The preparations used in all 4 cases were:

Human Menopausal Gonadotrophin (HMG) containing menotrophin corresponding to 75 IU of FSH and 75 IU of LH per ampoule.

Human Chorionic Gonadotrophin (HCG) containing 5000 IU of chorionic gonadotrophin per ampoule.

Biosynthetic Human Growth Hormone (B-hGH) containing 20 IU of hGH per vial.

EXAMPLE 1

In vivo fertilization

Name: JN

Age: 35

Previous medical history: menarche (first bleedings) at the age of 15. Regular menstrual cycles for two years, but secondary amenorrhea (absence of the menstrual bleedings) since the age of 17. Failed to respond to clomiphene and therefore had HMG and HCG treatment for 12 cycles after which she conceived and delivered five years ago. For the last two years she has had HMG treatment with up to 80 ampoules of HMG per cycle, with no response (very low oestrogen levels and no follicular development).

First treatment cycle: (without B-hGH) Daily injections of increasing doses of HMG for 35 days (totally 60 ampoules) followed by injection of 10,000 IU of HCG to induce ovulation. No satisfactory follicular development.

Second treatment cycle: (with B-hGH) Daily injections of increasing doses of HMG for 21 days (totally 28 ampoules) followed by injection of 10,000 IU of HCG. During the same period the patient received injections of B-hGH: 20 IU administered three times per week (totally 180 IU of B-hGH). Eight well-defined follicles were performed.

Third treatment cycle: (with B-hGH) Treatment regimen as above. Totally 23 ampoules of HMG injected during 18 days followed by 10,000 IU of HCG. B-hGH: 160 IU totally. Formation of 9 well-defined follicles.

EXAMPLE 2

In vivo fertilization

Name: PR

Age: 39

Previous medical history: primary amenorrhoea. No response to clomiphene. No response to LHRH (Luteinizing hormone-releasing hormone). Had HMG and HCG treatment for about a year and needed 70-75 ampoules of HMG per cycle.

First treatment cycle: (without B-hGH)

During 29 days injection of totally 70 ampoules of HMG (followed by 10,000 IU and HCG) to incude formation of follicles.

Second treatment cycle: (with B-hGH)

Duration of treatment: 19 days

HMG: 35 ampoules

HCG: 10,000 IU

B-hGH: 120 IU

Result: formation of 6 follicles.

Third treatment cycle: (with B-hGH)

Duration of treatment: 12 days

HMG: 29 ampoules

HCG: 10,000 IU

B-hGH: 100 IU

Result: formation of 8 follicles.

EXAMPLE 3

In vitro fertilization

Name: LLC

Age: 39

Previous medical history: menarche at the age of 11. Irregular cycles. 20 years ago--spontaneous pregnancy and delivery. In the last few years she has had clomiphene, gonadotrophins alone and with LHRH preparations and several in vitro fertilization attempts. There were difficulties in getting good eggs from this patient and this patient needed up to 160 ampoules of HMG to get a maximum of 2 eggs.

March 1987 treated with 33 ampoules of HMG for 11 days and 100 IU of B-hGH. Formation of 10 eggs, 3 of which were fertilized.

EXAMPLE 4

In vitro fertilization

Name: SH

Age: 38

Previous medical history: in 1982 ectopic pregnancy (development of a fetus at a site other than in the uterus) resulting in operation of the right Fallopian tube (salpingectomy). In 1983 surgery on the left Fallopian tube. Two years later--diagnose: massive pelvic adhesions. For the last two years treatment with clomiphene and HMG and several in vitro fertilization attempts.

November 1986 treated with 20 ampoules of HMG and buserelin (=gonadotrophin releasing hormone) as well as B-hGH resulting in the formation of 3 eggs, 2 of which were fertilized. One of the fertilized eggs was succesfully implanted in the uterus so that the patient becase pregnant.

Synergistic Effect of Biosynthetic Human Growth Hormone (Norditropin®) and Gonadotrophin in the Rat Methods Experimental Animals

Female Sprague Dawley rats of the strain Crl:CD® (SD)BR were purchased at the age of 17-19 days, 30-33 g b. wt. from Charles River Wiga GmbH, Sandhoferweg 7, D-8741 Sulzfeld 1, BRD.

The rats were acclimatized for four days before use at 22±2° C., 55±10% relative humidity, air change ten times an hour and light on from 6.30 to 18.30 h. During the acclimatization period the rats were housed with their mothers in rectangular Orth plastic cages, 27×35×16 cm with pine bedding type Hahnflock H 3/4 from Hahn & Co. Kronsburg, D-2371 Bredenbek, BRD. The animals had free access to Altromin diet 1324 (from Chr. Petersen A/S, DK-4100 Ringsted) and drinking water.

From sets of six litter mates, one litter mate from each set was randomnly allotted to each of six groups and marked according to litter. Six groups of eight rats were formed per experiment.

Hypophysectomy

Hypophysectomy was performed after the acclimatization period, when the rats were 21-23 days old. The rats were anaesthetized with amylenhydrate (10% in 0.9% saline), 4-5 ml/kg b. wt. in addition to 4-5 ml/kg Brietal® (10 mg/ml 0.9% saline) intraperitoneally. For the hypophysectomy use was made of a special apparatus described by R. Illhardt (5). After cutting the lower part of the ear the rats were fixated in the apparatus for transauricular hypophysectomy. A cannula was inserted into the hypophyseal area and the hypophysis was sucked out with a vacuum of 200-400 mm Hg. A cotton wool tampon was placed in the ear after the operation, and postoperatively the rats were treated with two daily injections (for two days) of Temgesic® for analgesia.

The rats were weighed before hypophysectomy and 14 days after (before use in the experiment), and only animals with a weight gain <10 g and a weight loss <4 g and in good health were used in the experiment.

Dosing

Groups of 8 hypophysectomized rats were given doses of Pergonal (Serono Menotrophine), 0.5 IU, 1.0 IU and 1.5 IU, besides biosynthetic human growth hormone (Norditropin®) or buffer (Nanormon®) containing 20 g glycine, 2.5 g sodiumhydrogencarbonate, 2.0 g mannitol, and water for injections, to make 1000 ml. This buffer was used as a placebo. The three doses of Pergonal, which were chosen from the steep part of the dose response curve for Pergonal, were dissolved in 0.5 ml volumes of albumin-phosphate buffer pH 7.2 containing 14 IU of Chorionic Gonadotrophin (28 IU/ml). The doses were administered by subcutaneous injection three times with 24 hour intervals.

In one experiment 0.4 mg Norditropin® was administered in 0.5 ml volumes subcutaneously for three days to three groups given the three Pergonal doses, and 0.5 ml Nanormon® buffer was administered to three groups injected with the same three Pergonal doses. In a second experiment the same dose regimen was followed, only the Norditropin® dose was 0.6 mg in 0.5 ml.

About 24 hours after the last injection, the rats were killed by cervical dislocation and the ovaries removed and weighed immediately. The combined weight of both ovaries was recorded and used as test result for the individual rat.

Results

The data obtained are shown in tables 1-2. The tables show the ovary weights for the various dose groups, means ±S.E.M. The results for the Norditropin® injected groups were compared to the similar Nanormon® buffer injected groups using a student's t-test.

The rats injected with Pergonal+Norditropin® had significantly higher ovary weights than the rats injected with Pergonal+buffer. Norditropin® shifted the dose response curve for Pergonal to the left. A maximal effect on the ovary weight seems to be reached by the combination of 1.0-1.5 IU Pergonal+0.6 mg Norditropin® (table 2).

                                      TABLE 1                                      __________________________________________________________________________     Weight of ovaries from hypophysectomized rats injected with                    Pergonal and Norditropin ® or Nanormon ® buffer                        __________________________________________________________________________     Doses 0.5 IU 1.0 IU 1.5 IU 0.5 IU 1.0 IU 1.5 IU                                admini-                                                                              Pergonal +                                                                            Pergonal +                                                                            Pergonal +                                                                            Pergonal +                                                                            Pergonal +                                                                            Pergonal +                            stered                                                                               buffer buffer buffer 0.4 mg 0.4 mg 0.4 mg                                for                        Nordi- Nordi- Nordi-                                three days                 tropin ®                                                                          tropin ®                                                                          tropin ®                          Weight                                                                               0.017 ±                                                                            0.027 ±                                                                            0.029 ±                                                                            0.022* ±                                                                           0.033* ±                                                                           0.038* ±                           of ovaries                                                                           0.001  0.002  0.004  0.002  0.002  0.002                                 (g), X ±                                                                          N = 8  N = 8  N = 5  N = 8  N = 8  N = 8                                 S.E.M.                                                                         __________________________________________________________________________      *p <0.05 (student's ttest)                                               

                                      TABLE 2                                      __________________________________________________________________________     Doses 0.5 IU 1.0 IU 1.5 IU 0.5 IU 1.0 IU 1.5 IU                                admini-                                                                              Pergonal +                                                                            Pergonal +                                                                            Pergonal +                                                                            Pergonal +                                                                            Pergonal +                                                                            Pergonal +                            stered                                                                               buffer buffer buffer 0.6 mg 0.6 mg 0.6 mg                                for                        Nordi- Nordi- Nordi-                                three days                 tropin ®                                                                          tropin ®                                                                          tropin ®                          Weight                                                                               0.019 ±                                                                            0.024 ±                                                                            0.033 ±                                                                            0.024 ±                                                                            0.044*** ±                                                                         0.044 ±                            of ovaries                                                                           0.003  0.002  0.004  0.002  0.003  0.004                                 (g), X ±                                                                          N = 6  N = 7  N = 6  N = 7  N = 8  N = 7                                 S.E.M.                                                                         __________________________________________________________________________      ***p <0.001 (student's ttest)                                            

REFERENCES

1. Adashi et al.: Insulin-like growth factors as intra-ovarian regulators of granulosa cell growth and function; Endocrine Reviews 6: 400-420 (1985).

2. Ying et al.: Inhibin and beta-type transforming growth factor have opposite effects on the follicle stimulating hormone induced aromatase activity of cultured rat granulosa cells; Bioch Biophys Res Commun 136: 969-975 (1986).

3. Benjamin Davoren and Hsueh A J W: Growth hormone increases ovarian levels of immunoreactive somatomedin-C/insulin-like growth factor-I in vivo; Endocrinology 118: 888-890 (1986).

4. Hull M G R et al.: Population study of causes, treatment, and outcome of infertility; British Med J 291: 1693-1697 (1985).

5. Illhardt, R., 1971: Erfahrungen mit einer Spezialapparatur zur transaurikularen Hypophysektomie bei Ratten; Z. med. Labortechn. 12: 303-306. 

I claim:
 1. In a process for treating infertility caused by abnormal gonadotrophin secretion in mature higher female mammals wherein said mammals are injected with gonadotrophins to stimulate ovarian function, the improvement comprising administering growth hormone to said mammals in combination with said gonadotrophins, said growth hormone being administered in an amount effective to enhance said stimulation of the ovarian function in said mammals.
 2. A process as claimed in claim 1 wherein the gonadotrophins and the growth hormone are administered by injection either as a mixture or as separate components.
 3. A process according to claim 1, in which the growth hormone is specific to the treated species in question.
 4. A process according to claim 1, in which infertile farm animals are treated.
 5. A process according to claim 1, in which infertile women are treated.
 6. A process as claimed in claim 5 wherein the gonadotrophins injected comprise approximately equal amounts of FSH and LH and wherein each of said gonadotrophins is injected in a total dose about 10-22 times greater than the total dose of growth hormone administered.
 7. A process as claimed in claim 6 wherein the gonadotrophins and the growth hormone are administered at regular intervals over a period of from about 12-21 days.
 8. A process as claimed in claim 7 wherein the growth hormone is administered in a total amount of from 100-180 IU over said period.
 9. A process as claimed in claim 8 wherein the gonadotrophins injected further comprise 10,000 IU of human chorionic gonadotrophin.
 10. A process as claimed in claim 5 wherein the gonadotrophins injected comprise FSH and LH and wherein said gonadotrophins are injected in a total dose about 50 times greater than the total dose of growth hormone administered.
 11. A process as claimed in claim 10 wherein the growth hormone is administered over a period of about 11 days in a total amount of about 100 IU over said period.
 12. A process as claimed in claim 5 wherein the growth hormone is administered at an average daily dosage of about 6-9 IU. 